There have been known powder containers of a type that rotates a container body containing developer therein to thereby release toner through a discharge port. Some group of such rotating-type powder containers includes, on or near the bottom of the container, a protrusion that is brought into engagement with a distal end of a rotary shaft to transmit a driving force to the container body and rotate the container body. Other group of the rotating-type powder containers includes, in a portion of the powder container, a drive transmission member that rotates the container body when receiving a driving force. An example of the former is disclosed in Japanese Patent Application Laid-open No. H09-6115, while an example of the latter is disclosed in Japanese Patent Application Laid-open No. 2007-178969.
Some group of the conventional rotating-type powder containers is configured as follows: at shipment from a factory, the powder container is placed in a closed state where the discharge port is covered with a shutter provided on a cover member rotatable relative to the container body; the shutter is opened when the powder container is loaded on an apparatus and the container body is rotated. Other group is configured as follows: the discharge port is placed in a closed state with a cap; when the power container is loaded on an apparatus, the cap is removed to open the discharge port. At factory shipment, each of these two groups of powder containers is sealed with the cap, which is to be removed when the powder container is to be used. The cap is desirably efficiently attached to the container during assembly.
It is therefore an object of the present invention to provide a cap, for a powder container, exhibiting favorable operability to open and close a discharge port of the powder container, a powder container including the cap, and an image forming apparatus including the cap.